This invention relates to apparatus for the rapid homogeneous discharge of fine powder for use in the extinguishing of fires as well as other situations requiring the rapid dispersion of fine powder. More particularly, the invention relates to powder discharge apparatus wherein the powder is contained under pressure in a chamber or bottle and mixed with a compressed propellant fluid such as an inert gas wherein the powder and the propellant fluid can be discharged rapidly upon a fracturing of a diaphragm of the chamber.
The discharge of powdered material is employed in a wide variety of situations ranging from the extinguishing of fires to the dispersement of agricultural material, such as insecticides, on farms. In the case of a hand-held fire extinguisher charged with a powdered fire suppressant, the powder is ejected in a steady stream under pressure by a gaseous propellant. However, there are situations in which all of the powder is to be discharged almost instantaneously, for example within a few milliseconds, such a situation arising in the extinguishing of fires in an aircraft.
A problem arises in the extinguishing of fires in an aircraft because of the need for a sudden discharge of the powdered fire-repellant material. Typically, fire-fighting equipment installed on aircraft must operate automatically in response to an explosive fire in order to be effective. The sensor, as is well known, operates via an electrical circuit to fire a detonator or squib to explosively eject powder from a container thereof throughout a region of the aircraft protected by the fire-fighting equipment.
The powdered fire-suppressant material operates most effectively when the material is dispersed as a fine powder throughout the region affected by the fire. However, in the prior art, the explosive force of the squib tends to compact the powder with the undesirable result of forming clumps of the material which hinder the effectiveness of the powder in extinguishing a fire.
A further consideration in the use of the foregoing fire-extinguishing equipment is the construction of the equipment as self-contained modules. In the past, a problem has arisen in that the electronic circuitry employed in automatic activation of the fire-extinguishing equipment on board aircraft has employed electrical power supplied by the aircraft, such power being applied typically at 28 volts. The use of the aircraft power has necessitated the installation of electrical cabling with the consequent inconvenience of incorporating all such wiring within instruction manuals employed in the manufacture and servicing of the aircraft. Such cabling is disadvantageous in combat situations wherein shrapnel produced by an explosion might possibly sever the cabling resulting in a disabling of the fire-extinguishing equipment.